Run results for: Number & toLocaleString vs + & toLocaleString vs custom thousands seperator

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:121.0) Gecko/20100101 Firefox/121.0

Browser: Firefox 121

Operating system: Linux

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
toLocaleString	3144722.0 Ops/sec
custom thousands seperator	4399667.0 Ops/sec
toLocaleString +	3034322.0 Ops/sec

Script Preparation code:

var number = '1234567';

var addThousandsSeperators = (value) => {
  if (value.length <= 3) return value;
  return Array.from(value).reduce((acc, x, i, a) => (
    (a.length - i) % 3 === 0 && i ? `${acc},${x}` : `${acc}${x}`
  ), '');
};

Tests:

toLocaleString
Number(number).toLocaleString();
custom thousands seperator
addThousandsSeperators(number);
toLocaleString +
(+number).toLocaleString();

Run results for: Number & toLocaleString vs + & toLocaleString vs custom thousands seperator

toLocaleString

custom thousands seperator

toLocaleString +